1. Field of the Invention
This disclosure relates to personal computer systems and more particularly to a power on timer that can be used to measure or record the amount of time a personal computer system is powered on.
2. Description of Related Art
Personal computer (PC) systems in general and IBM personal computers in particular have attained widespread use for providing computer power to many segments of today's modern society. Personal computer systems can usually be defined as a desk top, floor standing, or portable microcomputer that consists of a system unit having a single system processor and associated volatile and non-volatile memory, a display monitor, a keyboard, one or more electromechanical direct access storage devices (DASD), and an optional printer. One of the distinguishing characteristics of these systems is the use of a motherboard or system planar board to electrically connect these components. These systems are designed primarily to give independent computing power to a single user and are inexpensively priced for purchase by individuals or small businesses. Examples of such personal computer systems are IBM's Personal Computer AT and IBM's Personal System/2 Models 25, 30, 50, 60, 70 and 80. Personal computers occasionally encounter intermittent errors. An intermittent error is an error that is detectable but not repeatable by known means. When diagnosing intermittent problems, it is helpful to learn the amount of time between intermittent problems. The time that is useful is not the total elapsed time on a clock between the two events, but the amount of use or time the system is powered-on between the two events. This power-on-time (POT) can be very helpful to service personnel in debugging intermittent problems which cannot be readily reproduced due to its cause being unknown. The power-on-time is also helpful for estimating service costs and the mean time between failure values for the PC system.
There are two methods that can be used to obtain the POT. One is a separate power-on-time meter, similar to those used on computer mainframes such as an IBM 3970. The second is to physically time the power-on-time manually. In the cost competitive environment that personal computers are marketed, the use of a separate POT meter is not practical. Currently, there are no PCs in the industry with power-on-time meters, so the extra cost of a meter will make a PC having such a meter non-competitive. The second method of manually timing the systems power-on-time is not practical or reliable. The duration between events may be on the order of weeks or months. Using manual logs to track the power-on-time in most cases will be unreliable. People forget to log in or just don't do it. Bear in mind that a single PC can be available to many users, which compounds the problem of manual logging of usage.
It is therefore desirable to provide a reliable and inexpensive power-on-time meter that can be integrated into current PCs to perform the function of a hardware power-on-time meter.